Poly lysine

A. Brush Layers of Poly(glutamic acid) and Poly(lysine)... 

An essential prerequirement for the aggregation is the presence of different epitopes on the antigenes so that their functionality is greater than one. Reversible bridging flocculation of poly(lysine) with acrylic microgels has also been reported [376]. 

Electrophoresis is normally run in aqueous media, hence the analytes must be soluble in water. Presently only three types of water-soluble dendrimers have been successfully analyzed using gel electrophoresis techniques. The list includes Starburst PAMAM dendrimers [21], nucleic acid dendrimers [21] and poly(lysine) dendrimers [23, 24] (see Figures 10.2, 10.4 and 10.6). However, in each case appropriate water solubilizing terminal groups are required (i.e. -NH2, -OH or C02H groups) for suitable electrophoretic analysis. 

For comparison, linear and dendritic poly(lysine)s were analyzed in a parallel study using PAGE [21], The linear poly(lysine), with a reported polydispersity of... 

Figure 10.3 Electrophoretogram of several generations of (EDA-core) PAMAM dendrimers (E 0-10). The unlabeled smear in the middle of the gel is a conventional polydispersed linear poly(lysine) sample as a comparison...

Figure 10.5 Electrophoretogram of linear poly(lysine) (left) and dendritic poly(lysine)s (D 3-7).

Formation of a complex between DNA and polycationic compounds appears to be the initial and quite possibly a critical parameter for nonviral gene delivery. Several synthetic vector systems, which are generally cationic in nature, including poly(lysines), cationic liposomes or various types of block copolymers and recently dendrimers, have been shown to self-assemble with plasmid DNA [13-15] [16]. Specific physicochemical properties manifested by these DNA complexes depend on the type of cationic agent used however, interesting patterns for such interactions are beginning to evolve [17, 18]. Under certain conditions, the interaction of DNA with polyvalent cations results in... 

In both cases the top layer of these layered polyelectrolyte films contains many ion sites that can bind redox ions by ion exchange vdth the electrolyte solution. Homo polypeptides such as poly(L-lysine) and poly(L-glutamic add) have been employed to form layered polyelectrolyte films with Fe(CN)6 " electrostatically adsorbed onto ammonium sites in poly(lysine) [45]. Modified electrodes with polyelectrolytes mono-layers have also been deposited using the Langmuir-Blodgett technique [46-48]. 

J. Lucassen, F. Hollway, and J.H. Buckingham Surface Properties of Mixed Solutions of Poly-Lysine and Sodium Dodecyl Sulfate. 2. Dynamic Surface Properties. J. Colloid Interface Sci. 67, 432 (1978). 

The immobilisation by electrostatic interactions of longer, 26 bp ssDNA strands on hard, poly(lysine)-coated glass resulted in aggregates of 63 nm (Fig. 26) [163]. Finally, when DNA molecules of the same length (26 bp) were covalently immobilised on the surface of plasma-induced, NHS-... 

Other mechanistic ideas The most obvious problem with the colloidal crystal model is that it is hard to reconcile with the tracer diffusion experiments on poly (lysine) (15.) that do not detect any long-lived, slowly diffusing aggregates. While this type of experiment has not yet been done with DNA, it is reasonable to expect that the same result would be found. 

Dissolved polymer molecules can be adsorbed by polymer particles via electrostatic attractive force or hydrophobic interaction. When polyelectrolyte is adsorbed on an opposite-charge particle, the polymer molecules usually have a loop-and-tail conformation and, as a result, inversion of charge occurs. For example, sulfatecarrying particles behave as cationic ones after they adsorb poly(lysine). Then poly(-styrene sulfonate) can be adsorbed on such cationic particles and reinvert the charge of particles to anionic (14). Okubo et al. pointed out that the alternate adsorption of cationic and anionic polymers formed a piled layer of polyelectrolytes on the particle, but the increment of adsorbed layer thickness was much less than expected. This was attributed to synchronized piling of two oppositely charged polyelectrolytes (15). 

Dupuy, B., Alien, A., and Minnot, A.P. (1994). FT-IR of membranes made with alginate/poly-lysine complexes—variations with the mannuronic or guluronic content of the polysaccharides. Artif. Cells. Blood Substit. Immobil. Biotechnol., 22, 143-151. 

A wave of excitement was set in motion by this discovery. Soon afterwards it was demonstrated that poly (A) promotes poly lysine synthesis and poly(C) promotes polyproline synthesis. From these observations it seemed clear that the code words UUU, AAA, and CCC correspond to the amino acids phenylalanine, lysine, and proline, respectively. 

Figure 8. Transmission electron micrograph of aggregates of RBCs in poly lysine (19). Note the nonuniform intercellular spacing which contains strands of polylysine molecules (70,000X magnification).

Laemmli, U.K. (1975) Characterization of DNA condensates induced by poly (ethylene oxide) and poly lysine. Proc. Natl. Acd. Sci. USA, 72, 4288M292. 

Poly(ethylene oxide )-g-poly (/.-lysine) (PEO-g-PLL) Graft copolymer In vitro and in vivo transfection, delivery of oligonucleotides Choi etal, 1998)... 

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